Developing a Project Plan Answer Key Part 3

60. An activity has a duration of 10 days. Its early start is 4 and its late start is 6. This activity has _____ days of total slack. 2 Total slack tells us the amount of time an activity can be delayed and yet not delay the project. Stated differently, total slack is the amount of time an activity can exceed its early finish date without affecting the project end date or an imposed completion date. It is calculated by subtracting the late start from the early start. In this case, this activity has 2 days of slack. 61. ________ can never be negative and applies only to the last activity in a single chain of activities. Free slack Free slack is the amount of time an activity can be delayed without delaying any immediately following (successor) activity. Or, free slack is the amount of time an activity can exceed its early finish date without affecting the early start date of any successor(s). Free slack can never be negative. 62. A(n) ________ is the minimum amount of time a dependent activity must be delayed to begin or end. lag A lag is the minimum amount of time a dependent activity must be delayed to begin or end. 63. When an activity with a long duration is broken into smaller segments so that the following activities can begin sooner it is called __________. laddering The assumption that all immediate preceding activities must be 100 percent complete is too restrictive for some situations found in practice. This restriction occurs most frequently when one activity overlaps the start of another and has a long duration. Under the standard finish-to-start relationship, when an activity has a long duration and will delay the start of an activity immediately following it, the activity can be broken into segments and the network drawn using a laddering approach so the following activity can begin sooner and not delay the work. 64. The longest path through a project network is called the _________. critical path The critical path is the network path that has the least slack in common. It is the longest path through the network and its duration determines the duration of the project. 65. ___________ reflects the likelihood the original critical path(s) will change once the project is initiated. Sensitivity Sensitivity reflects the likelihood the original critical path(s) will change once the project is initiated. Sensitivity is a function of the number of critical or near-critical paths. 66. A network has only one critical path and the slack for noncritical activities is high. This network would appear to have a _______ level of sensitivity. low Network sensitivity is a function of the number of critical paths and the level of slack for noncritical activities. Since this project has only one critical path and the level of slack for noncritical activities is high, it would appear to have a low level of sensitivity. 67. The _________ lag is the most typical type of lag that is encountered in developing networks. finish to start The finish-to-start relationship represents the typical, generic network; however, there are situations in which the next activity in a sequence must be delayed even when the preceding activity is complete. 68. A(n) __________ activity is frequently used to identify the use of fixed resources or costs over a segment of the project. hammock Hammock activities are frequently used to identify the use of fixed resources or costs over a segment of the project. Typical examples of hammock activities are inspection services, consultants, or construction management services. A hammock activity derives its duration from the time span between other activities. For example, a special color copy machine is needed for a segment of a tradeshow publication project. A hammock activity can be used to indicate the need for this resource and to apply costs over this segment of the project. True / False Questions 69. An activity can include only one work package. FALSE Activities usually represent one or more tasks from a work package. 70. A merge activity is one that merges with other activities into a succeeding activity. FALSE A merge activity is an activity that has more than one activity immediately preceding it (more than one dependency arrow flowing into it). 71. The WBS identifies dependencies, the sequencing of activities, and the timing of activities. FALSE Networks provide the project schedule by identifying dependencies, sequencing, and timing of activities, which the WBS is not designed to do. 72. The critical path is the shortest path through a network and indicates activities that cannot be delayed without delaying the project. FALSE Critical path means the path(s) with the longest duration through the network. If an activity on the critical path is delayed, the project is delayed the same amount of time. 73. An activity is an element of the project that always requires time. TRUE An activity is an element of the project that requires time. It may or may not require resources. 74. If a network has more than one critical path but noncritical activities have very little slack, the network is considered to have a high level of sensitivity. TRUE Network sensitivity is a function of the number of critical paths and the level of slack for noncritical activities. Since this network has more than one critical path and the level of slack for noncritical activities is low, it would appear to have a high level of sensitivity. 75. The backward pass determines project duration. FALSE The forward pass determines the early start and finish for activities. It also determines the early finish of the project. 76. An activity cannot begin until ALL preceding connected activities have been completed. TRUE All preceding activities must be completed before an activity can begin. 77. In developing a project network, neither looping nor conditional statements are permitted. TRUE Looping is not allowed (in other words, recycling through a set of activities cannot take place). Also conditional statements are not allowed (that is, this type of statement should not appear: If successful, do something; if not, do nothing). 78. Experience suggests that when there are multiple starts, a common start node should be used to indicate a clear project beginning on the network. Similarly, a single project end node can be used to indicate a clear ending. TRUE Experience suggests that when there are multiple starts, a common start node can be used to indicate a clear project beginning on the network. Similarly, a single project end node can be used to indicate a clear ending. This helps to identify the total planning period of the project. 79. Burst activities have more than one activity immediately following them (more than one dependency arrow flowing from them). TRUE Burst activities have more than one activity immediately following them (more than one dependency arrow flowing from them). 80. It is acceptable for arrows to cross one another in a network diagram. TRUE Arrows on networks indicate precedence and flow. Arrows can cross over each other. 81. The forward pass through a project network determines the critical path. FALSE The forward pass starts with the first project activity(ies) and traces each path (chain of sequential activities) through the network to the last project activity(ies). The forward pass assumes every activity will start the instant in time when the last of its predecessors is finished. It determines the early start and early finish for activities and the project duration. The backward pass determines the critical path. 82. The backward pass through a project network determines slack or how long an activity can be delayed without impacting the completion date of the project. TRUE The backward pass represents the critical path. The critical path is the longest path in the network, which, when delayed, will delay the project and determines how long the activity can be delayed without delaying the project. 83. Different activities along the same path can have different total slack. TRUE If slack of one activity in a path is used, the ES for all activities that follow in the chain will be delayed and their slack reduced. Use of total slack must be coordinated with all participants in the activities that follow in the chain. 84. If the project has a duration of 13 days, the project should be completed 13 days from the day it starts. FALSE After determining a project's duration, you will need to assign calendar dates to your project. You will need to consider weekends and holidays when determining the completion date. 85. It is possible for a project network to have more than one critical path. TRUE Critical path means the path(s) with the longest duration through the network. If an activity on the critical path is delayed, the project is delayed the same amount of time. A network may have multiple critical activities resulting in multiple critical paths. 86. Using free slack does not delay any following activities and requires no coordination with managers of other activities. TRUE Free slack is the amount of time an activity can be delayed without delaying any immediately following (successor) activity. Or, free slack is the amount of time an activity can exceed its early finish date without affecting the early start date of any successor(s). 87. Gantt charts are popular because they represent an easy-to-understand, clear picture on a time-scaled horizon. TRUE Gantt charts are used for planning, resource scheduling and status reporting. The format is a twodimensional representation of the project schedule, with activities down the rows and time across the horizontal axis. 88. When completing a forward pass, you carry the early finish to the next activity where it becomes its early start unless the next succeeding activity is a merge activity. In this case you select the smallest early finish number of all its immediate predecessor activities. FALSE When completing a forward pass, you carry the early finish to the next activity where it becomes its early start unless the next succeeding activity is a merge activity. In this case you select the largest early finish number of all its immediate predecessor activities. This makes sense because all preceding activities must be complete before an activity can start. 89. Only activities that occur at the end of a chain of activities can have free slack. TRUE Free slack occurs at the last activity in a chain of activities. Using this slack does not have to be coordinated with managers of succeeding activities. 90. Lags can be used to constrain the start and finish of an activity. TRUE Lags are used when activities of long duration delay the start or finish of successor activities. The network designer normally breaks the activity into smaller activities to avoid the long delay of the successor activity. Using lags can avoid such delays and reduce network detail. Lags can also be used to constrain the start and finish of an activity. 91. Even though a project costs time and money to develop, it is worth the effort. TRUE This is true in the value that it adds for planning and understanding how the project is proceeding. The only time it is not valuable is when the project is very short in duration or considered trivial. 92. Within an Activity-on-Node network, the arrows depict activities to be accomplished. FALSE Activity-on-Node networks have the activities on the node, whereas the dependencies are indicated by the arrows. 93. Negative slack can be estimated. FALSE Negative slack can only be calculated once the critical path has been delayed. Short Answer Questions 94. How does the WBS differ from the project network? How are WBS and project networks linked? The network is developed from the information collected from the WBS and is a graphic flow chart of the project job plan. Networks provide the project schedule by identifying dependencies, sequencing, and timing of activities the WBS is not designed to do. 95. Briefly describe looping and conditional statements and explain why they are not allowed when developing project networks. Looping is the attempt by the network designer to return to an earlier activity. If looping were allowed paths would continuously repeat themselves. Conditional statements are "if/then" statements. If conditional statements were allowed, the network would make little sense and would not be able to accomplish many of its objectives. 96. When completing the forward pass, the project duration is determined. A project duration of 90 days doesn't mean that if the project were to start today it would be complete in 90 days. Explain. The project duration gives you an estimated number of working days necessary to complete the project. It doesn't consider weekends, holidays, overtime, etc. 97. In the network computation process what is a forward pass and what three things does it determine? Starting with the first activity, each path is traced forward through the network, adding times until the end of the project. This determines (1) how soon each activity can start, (2) how soon each activity can finish, and (3) how soon the entire project can be completed. 98. In the network computation process what is a backward pass and what four things does it determine? Starting with the last activity, each path is traced backward through the network, subtracting times until the beginning of the project. This determines (1) how late each activity can start, (2) how late each activity can finish, (3) the critical path, and (4) how long each activity can be delayed without changing the completion date. 99. What is the difference between free slack and total slack? Total slack tells us the amount of time an activity can be delayed and not delay the project. Use of total slack must be coordinated with all participants in the activities that follow in the chain. Free slack is the amount of time an activity can be delayed without delaying any immediately following activity. It requires no coordination with other managers. 100. What is a Gantt chart and what advantages does it have over project networks? Gantt charts are bar charts where activities are displayed as bars on a horizontal time-scale. They are easy-to-read and provide a clear overview of the project schedule and progress against that schedule. 101. When completing a forward pass you carry the early finish to the next activity where it becomes its early start, unless the next succeeding activity is a merge activity. In this case you select the largest early finish number of all its immediate predecessor activities. Why do you select the largest early finish number? Acknowledging that the finish number represents the activities' early finish, the largest early finish number is selected because all preceding activities must be completed before an activity can begin. If anything less than the largest number is chosen, there will not be enough time for all preceding activities to finish. 102. What is a lag and give an example of when you would need to use one? A lag is the minimum amount of time a dependent activity must be delayed to begin or end. Lags occur during laddering and avoid delays and they are also used to constraint the start and finish of an activity. 103. What is a hammock activity and give an example? A hammock activity identifies the use of a resource over a segment of the project. Thus its duration is determined by the duration of other activities. The example used in the text was for a color copier during specific phases of a project. 104. What is the Concurrent Engineering Approach and why should project managers be aware of it? The chainlike sequence of finish-to-start relationships is replaced by a series of start-to-start lag relationships as soon as meaningful work can be initiated for the next phase. The resulting overlap of tasks slightly increases risk but results in a much shorter schedule. 105. Identify and briefly describe the four types of lags giving an example for each type. (1) Finish-to-Start; (2) Start-to-Start; (3) Finish-to-Finish; (4) Start-to-Finish.